Dear all, I was reading this https://sites.google.com/site/gener...-the-covariant-derivative-of-the-ricci-tensor, and it said that if you take the covariant derivative of a tensor with respect to a superscript, then the partial derivative term has a MINUS sign. How? The Christoffel symbol should have a minus sign, but I don't understand how does the partial derivative get one? Also, does covariant derivative always have an index opposite to that of the tensor(e.g. a contravariant tensor will be differentiated wrt a covariant tensor, and a covariant tensor wrt to a covariant index)? If so, why? Is there a relation between the two(which the minus sign mentioned above indicates)? Thanks in advance!!